<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
</head>
<body>
<h1>
    Turn UpperCase after input
</h1>

<hr>

<input type="text" name="name" onchange="turnUpperCase()" id="input"/>


<script>
    function turnUpperCase() {
        var x = document.getElementById("input");
        x.value = x.value.toUpperCase();
    }
</script>

</body>
</html>